Moderna Wins FDA Approval for First mRNA-Based Flu Shot

After months of regulatory delays and mounting public

After months of regulatory delays and mounting public pressure, the U.S. Food and Drug Administration has granted approval to Moderna's new influenza vaccine, marking a major milestone for messenger RNA technology beyond its use in COVID-19 shots.

The decision, announced on Friday, covers an mRNA vaccine designed to protect against seasonal flu strains. Unlike traditional flu shots, which are typically grown in chicken eggs or insect cells, this vaccine uses genetic instructions to prompt the body to build a viral protein, triggering an immune response without exposing recipients to the live virus.

Initially, the FDA had declined to even accept Moderna’s application for review, citing incomplete data on manufacturing consistency. But an unusual wave of criticism from patient advocates, public health experts, and lawmakers—who argued that the agency was being overly cautious given the urgent need for more effective flu vaccines—forced a reversal.

Moderna’s clinical trials involved over 23,000 adults ac…

Moderna’s clinical trials involved over 23,000 adults across multiple countries and showed the vaccine was about 83% effective against influenza A strains, outperforming standard shots in older adults, a group particularly vulnerable to severe flu complications. The company says it expects to begin shipping doses to clinics and pharmacies ahead of the next flu season.

Public health officials have welcomed the approval, noting that current flu vaccines reduce illness by only 40% to 60% in good years, and far less in mismatched seasons. The new mRNA platform could allow rapid updates to match circulating strains, a process that traditionally takes months.

Still, some independent researchers caution that long-term safety data is limited, and the vaccine’s effectiveness against influenza B strains remains less robust. Moderna has pledged to conduct post-market surveillance and continues to test a combined flu-COVID shot.

The approval is seen as a strategic win

The approval is seen as a strategic win for the biotech firm, which is working to diversify its pipeline as demand for its coronavirus vaccine has waned.